Railway traffic controlling apparatus



' March so, 1943 v E. ALLEN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed July 51, 1941 2 Sheets-Sheet 1 IINVENTOR Earl .1411912. BY

'HJS ATTORNEY March 30, 1943. E. M. ALLEN RAILWAY TRAFFIC CONTROLLING APPARATUS 2 Sheet-Sheef 2 Filed July 31, 1941 M R mum Kw N NNQN iw E MNQN w Q m Q3 53 g HIS ATTORNEY Patented Mar. 30, 1943 UNITED STATES P E 'E' F F i C E RAILWAY TRAFFIC CONTROLLING APPARATUS Application July 31, 1941, Serial No. 404,763

5 Claims.

My invention relates to railway trafiic controlling apparatus, and more particularly to such apparatus for controlling the signals of a trafilc route over which traflic may move in either direction.

Signals located at the opposite ends of a traflic route for controlling traffic in opposite directions over the route may be controlled by an interlocking, a remote control system or a centralized traflic control system. Whatever the system of control used, it is essential that each switch within the limits of the route be properly set before a signal can be cleared. Also it is desirable to prevent a so-called hidden lockout condition. Such hidden lockout may occur if an operator transmits a control influence for clearing a signal and such signal fails to respond for any reason to such control influence and th operator overlooks this condition and fails to transmit a control influence to cancel the control established by the first transmitted influence. This control condition established by the first influence remains stored and keeps in effect the electric locking against other signals associated with the first mentioned signal. Such electric locking becomes hard to locate because the operator has overlooked his neglect to cancel the control influence that caused it, and for this reason such lockout is commonly referred to as a hidden lockout, all

signals for the respective route being of course inoperative as long as this lockout exists. Again, when a signal at one end of the route has been cleared, it is essential that any inadvertent attempt on the part of th operator to clear the opposing signal is prevented from setting the cleared signal to stop. Furthermore, at interlockings it is desirable to prevent the establishing of a control for clearing the signal for a train to move over a route that conflicts with a route already in use. That is, it is essential that a train cannot be directed over a Wrong route.

In view of such circumstances in railway traffic controlling apparatus, a feature of my invention is the provision of railway tra-flic controlling anparatus incorporating novel means for controlling the opposing Signals of a route over which trafiic may move in either direction.

Another featur of my invention is the provision of railway traffic controlling apparatus incorporating novel means for preventing a socalled hidden lockout condition in the control of signals of a traffic route.

Again, a feature of my invention is the provision of apparatus of the type here involved wherewith the establishing of a control for a signal for a wrong route is avoided.

Other features, objects and advantages of my invention will become apparent from the following specification.

The above features, objects and advantages of my invention are attained by providing a route relay at each end of a traffic route over which trafiic may move in either direction, and by controlling each such route relay over a pick-up circuit and a stick circuit, which circuits in turn are governed by manually controlled means one for each end of the route. A pick-up circuit for a route relay is formed only when the manually controlled means at the same end of the route is operated, the route is properly conditioned for traffic, the signals are at stop, and the manually controlled means at the opposite end of the route is at its normal condition. The stick circuit for each route relay is closed only when the signal governed by that relay is cleared. The control influence forclosing a pick-up circuit for a route relay continues for a predetermined time interval only and hence if the intended signal fails to clear during such time interval the control influence becomes non-efiective. Thus when a manually controlled device or means is operated to close the pick-up circuit for a route relay and such control'influence persists for a predetermined time interval only, the route relay is not retained energized by its stickoircuit when the signal fails to clear, and the control influence is annulled. In other words, there is no storing of the control influence or code for clearing a signal with the result that a so-called hidden lockout condition is avoided. Also by such stick circuit control for a route relay that governs a signal at the corresponding end of a trafiic route, a signal once cleared to permit a movement into the route is not set to stop by any inadvertent operation of the manually controlled means at the opposite end of the route.

I also provide a check or repeater relay which is controlled by the controlling relays for ach switch of the traffic route as well as by indication and repeater relays controlled by the switch, such special check or repeater relay being energized only when there is agreement in the positions of the controlling and repeater relays associated with a switch. Contacts of such check relay are interposed in the pick-up circuit of the associated route relays. Hence if an operator after preparing a route for a train, erroneously attempts to clear a signal for the train to move over a wrong route, the route relays for such wrong route cannot respond to the control influence and the train is not directed to the wrong route.

I shall describe one form of apparatus embodying my invention, 'and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a diagrammatic view showing a typical track layout which the apparatus of my invention is adapted to control. Figs. 2 to 7, inclusive, when taken together constitute a diagrammatic view showing one form of apparatus embodying my invention arranged for governing the switches. and signalsof the track layout of Fig. 1. Similar reference characters refer to similar parts in each of the several views.

Referring to Fig. 1, while a specific track layout is disclosed, it is to be understood that the ap-.

paratus of my invention is adapted to control other track layouts that may involve entirely different combinations of" switches and signals,

the relatively simple layout shown, however, being adequate to illustrate the principles of my invention. Fig. 1 illustrates by a single line diagram, a stretch of double track railway the two tracks EB and WB of which are connected by a crossover 3. The movement of traffic over crossover 3 is governed by signals bearing the reference characters 2 and 8 with distinguishing prefixes of R and L to indicate the direction of traffic governed by the signal. According to standard practice, signals L2 and R8 are each provided with but one signal mechanism, while signals L8 and R2 are each provided with two signal mechanisms mounted on the same mast, signal L8 being. provided with signal mechanisms LAB and LB8, and signal R2 being provided with signal. mechanisms RAZ and BB2; Thus when crossover 3 occupies its normal position, signals R8 and LA8 are opposing signals for a route on track WB, signals L2 and RAZ are opposing: signals for a route on track EB, and when crossover 3 occupies its reverse position, signals RB2. and LB8 are opposing signals for a' route for traffic tomove from track WE to track EB or vice versa.

'Ihe rails of tracks EB and WE are formed into track sections by the usual insulated rail' joints, section [:T of track EB and section (T of track WBzin-cluding the respective switches of crossover. 3 and extending from one to the other of the respective opposing signals. The adjacent ap-- proach track sections areindicated by the reference characters R2T, R8T, LZT and L8T, respectively.. Each section is provided with a track circuit including a normally energized track relay, each track relay being identified by'the' reference character R; with a prefix indicating the track section.

In order to simplify the drawings and to enable. the circuits to be more readily traced, I have located in most instances the relay contacts remote from the winding of the relay, and contacts of; the usual controllers operated by the switches 3E and 3W' of the crossover remote from the switch. 'In each such case, the contact is identified by the reference character of theassociated' operating device as wellas by a distinctive numben. vAlso each. such contact is shown in a position corresponding to the normal position of the operating device.

Switches 3E and 3W of crossover 3' are actuated by power switch machines 35M and 3ASM, respectively. The. type of switch machine is immaterial, and they are shown in the drawing conventionally. It is sufiicient for the present application to point out that each switch machine includes a motor element and a driving mechanism by which the motor element is operatively connected to the switch so that when the motor element is energized over a first or normal operating circuit the mechanism is operated as required to move the switch to its normal position, and when the motor element is energized over a sec- 0nd or reverse operating circuit, the mechanism is operated as required to move the switch to its reverse position. The two switch machines are interconnected so that the two ends of the crossover agree in their positions. As shown in Fig. l, a normal operating circuit can be traced from terminal 13 of a convenient source of current, such. as a battery not shown, over front contact 4 of a normal switch controlling relay 3NWS to be referred to later, wire 5, motor element of switch machine 38M and wire 6 to terminal C of the same source of current. This normal operating circuit extends from switch machine 3SM over wire I to the motor element of switch machine tASM and wire 8 to-terminal C. A reverse operating circuit includes terminal B, front contact 9 of a reverse switch controlling relay ERWS, also to be referred to later, wire l0, motor element of switch machine 3SM, wire 6 and terminal C; and this circuit extends from switch machine 38M over wire ll, through the motor element of switch machine 3ASM and wire 8 to terminal C. Hence when normal switch controlling relay .iNWS is picked up, the crossover 3 is actuated to its normal position, and when reverse switch controlling relay SRWS is picked up, the crossover is actuated to its reverse position. The means for controlling relays 3NWS and SRWS will be later described.

Referring to Fig, 2, the switches of crossover 3 govern a switch indication relay 3KR. and switch repeater relays 3NKP and dRKP according to the positions of the switches. A normal energizing circuit for relay SKR is formed from terminal B over contacts l2 and I3 of the usual circuit controllers of switches 3E and 3W, respectively, and which contacts are closed at the normal position of the switches, winding of relay 3X12, contacts Hand l5 of the respective circuit controllers and terminal C. This circuit energizes relay 3KR at normal polarity to close its front neutral contact l6 and its normal polar contact ll. With the two switches occupying their reverse positions, a circuit is formed from terminal B over contact l8 of the controller for switch 3E, contact 14 of the controller for switch 3W, winding of relay 3KR, contacts l3 and IQ of the respective controllers and. to terminal C, and relay 3KR is energized at reverse polarity to close its front contact l6 and reverse polar contact 26. Relay 3KR in turn controls repeater relays 3NKP and 3RKP, the arrangement being such that normal switch repeater relay 3NKP is energized over an obvious circuit including front contact 16 and normal polar contact l l of relay 3KR, and reverse switch repeater relay 3RKP is energized over an obvious circuit including front contact I6 and reverse polar contact 29 of relay 3KR. As also shown in Fig. 2, the switch repeater relays 3NKP and SRKP, together with switch controlling relays 3NWS and BRWS, govern another repeater or check relay 3WPZ. When switch controlling relay 3NWS is picked up to close the normal switch operating circuit as shown inFig. 1 and normal switch repeater relay 3NKP is picked up due to the normal position of the switches 3E and 3W of the crossover, a circuit is formed from terminal B over front contact 2| of relay 3NKP, front contact 22 of relay 3NWS, back contact 23 of relay 3RWS, winding of relay 3WPZ and to terminal C, and relay SWPZ is picked up. Again, when the reverse switch controlling relay 3RWS is picked up to complete the reverse switch operating circuit as shown in Fig. 1, and repeater relay ARKP is picked up in response to the reverse position of the switches of the crossover, acircuit is formed from terminal B over back contact 24 of relay 3NKP, front contact 25 of relay 3RKP, front contact 25 of relay 3RWS, winding of relay 3WPZ and to terminal C, and relay 3WPZ is picked up, It follows that the check or repeater relay 3WPZ is picked up when there is agreement in position between the switch controlling relays of crossover 3 and the switch repeater relays governed by the switches of the crossover. The relays 3NKP, 3RKP and 3WPZ,

control the route locking circuit of Fig. '7 to be described hereinafter.

Referring to Fig. 3, an approach locking relay M is provided for each direction of traffic of each track EB and WB, the circuit for each such approach locking relay being substantially that in present day use and a description of the circuit for one such relay will suffice for an understanding of all. For example, approach locking relay RZM associated with eastbound traiiic on track E3 is controlled by a circuit formed from terminal B over front contact 124 of a signal repeater relay RZGP to be referred to later, back contact I25 of a route relay RZHS also to be referred to later, front contact I26 of track relay RZTR, winding of relay RZM and to terminal C. If signal repeater relay RZGP is released or route relay RZHS is picked up, approach locking relay RZM is released. In the event the approach section RET is occupied and signal R2 put to stop by the release of route relay R2HS in a manner to be later described, relay RZGP is picked up, relay REM is reenergized over a circuit including a front contact 21 of a time element relay ZTE. Relay 2TE will become enerenergized after a predetermined time interval I and picks up to close front contact 21 and cause relay RZM to be energized. If signal R2 is put to stop automatically by the passage of a train into section lT shunting track relaylTR and causing relay RZHS to be released as will later appear, the circuit of relay RZM is completed at back contact 29 of track relay ITR of section IT. The control circuit for approach locking relay RilM associated with eastbound movement on track WB, relay L8M associated with westbound movement on track WB and relay LZM associated with westbound movement on track EB will be readily understood from an inspection of Fig. 3 taken in connection with the description of the control circuit for relay RZM. These approach locking relays M are used not only in the usual manner to approach lock the switches of the crossover, but are also used to control the respective signal control networks as will be apparent when the signal control networks of Fig. 6 are described.

The signals shown in Fig. 1 may be of any suitable type and in accordance with standard practice the signals RAZ and LAZ govern high speed routes and will be the usual three-position signals governed in accordance with the condition of other signals in advance, not shown, in addition to being subject to manual and track circuit control. The remaining signals BB2, R8, LBS and L2 govern low speed routes and are two-position signals and are subject to manual and track circuit control. In the present embodiment of the invention, these signals are considered as being of the color light type, the operating or lighting circuits of each signal being governed by a signal control relay identified by the reference character H with a prefix corresponding to the respective signal.

Looking at Fig. 4, the operating circuits for signal RAZ are governed by a signal control relay RAZH and the circuits for signal R32 are governed by a signal control relay RB2H. When relay RAZH is picked up to close its front contact 30 and a relay RZD controlled by signals in advance is picked up to close front contact 3|, the G lamp of signal RA2 is illuminated as a clear signal indication. If relay RAZH is picked up to close front contact 30 and relay RZD is released closing back contact 32, the Y lamp of signal RAE is illuminated as an approach signal indication, and when relay RA2H is released to close back contact 33, the R lamp of signal RAZ is illuminated as a stop signal indication. Again, when relay RBZH is picked up to close front contact 34, the Y lamp of signal R32 is illuminated and when relay RBZH is released closing back contact 35 the R lamp of signal RBZ is illuminated. The operating circuits for illuminating the different lamps of the other signals will be apparent from an inspection of Fig. 4 taken in connection with the above description of the circuits of signals HA2 and RBZ.

Referring to Fig. 5, a signal repeater relay is provided for each signal of Fig. 1, such repeater relay being identified by the reference character GP with a prefix corresponding to the signal. For example, the signal repeater relay RZGP for signal R2 is normally energized over a circuit including terminal B, back contacts 36 and 31 of signal control relays RBZH and RAZH, respectively, windin of relay R2GP and terminal C. The signal repeater relay R8GP for signal .Rfi'is controlled over back contact 38 of signal control relay REH; repeater relay LZGP for signal L2 is controlled over back contact 39 of signal control relay L2H; and repeater relay LSGP for signal L8 is controlled over back contacts 40 and 4! of signal control relays LBSH and LASH. respectively. It follows that when a signal control relay is released to-set the corresponding signal tostop, the respective signal repeater relay is picked up and when the signal control relay is picked up to operate its corresponding signal to a proceed position, the respective repeater relay is released.

The signal control relays H are controlled over circuit networks illustrated in Fig. 6, the circuit network for each signal control relay H being controlled over front contacts of a rout-e relay HS for the corresponding signal and by a back contact of the route relay HS associated with the opposing signal, such route relays being con trolled by the circuit network of Fig. 7 shortly to be described. The signal control relay network is a counterpart of the track layout and includes a circuit for each direction for each route through the layout, each circuit being formed by conductors corresponding to portions of the track and connected together by contacts ccntrolled in accordance to the positions of the track switches. The circuit for each signal control relay also includes a front contact of the approach locking relay M associated with the opposing signal, thereby not only insuring that the signal cannot be cleared until the opposing signal indicates stop, but also interposing a time delay in the reversing of the direction of trafiic over a route when a signal is put to stop in the face of an approaching train.

Assuming the crossover 3 is normal and section IT of track EB is unoccupied, signal control relay RAZH is energized if route relay RZHS associated with signal RA2 is picked up and route relay LZHS associated with signal L2 is released. The circuit for relay RAZH includes terminal B, front contact 42 of opposing approach locking relay LEM, back contact d3 of opposing route relay LZHS, back contact i l of rela ZTE, normal polar contact 45 and front neutral contact 46 of indication relay SKR, front contact 4'! of route relay RZHS, back contact 43 of relay RZM, front contact 49 of track relay ITR, front contact 50 of switch repeater relay 3NKP, winding of relay RAZH, front contact of route relay REHS and terminal C. It is clear that in the event route relay LZHS is picked up in place of relay RBI-IS, the signal control relay L2H is provided with a circuit including terminal B, front contact 52 of relay R2M, back contact 53 of relay RZHS; contacts 46, 45 and 44, front contact 5A of relay LZHS, back contact '55 of relay LEM, front contact 56 of relay ITR, winding of relay L2H front contact 51 of relay LZHS and terminal C.

In the event crossover 3 occupies its normal position, and section 5T of track WB is unoccupied, and route relay L8HS associated with signal L3 is picked up, signal control relay LA8H is energized over a circuit extending from terminal B, front contact 58 of the opposing approach locking relay RBM, back contact 59 of the opposing route relay RRHS, normal polar contact 60 and front contact 6| of relay SKR, back contact 62 of relay BTE, front contact 63 of relay LQHS, back contact 6 1 of relay L8M, front contact 55 of relay 'lTR, front contact 66 of relay SNKP, winding of relay LA8H, front contact 67 of relay LBHS and to terminal G. In the event route relay RBHS associated with signal R8 is picked up then the signal control relay RBH is provided with a circuit including terminal front'contact 68 of relay LBM, back contact 63 of relay LBHS, contacts 62, 6| and 60, front contact of relay RBHS, back contact H of relay RGM, front contact 12 of relay 'ITR, winding of relay RBH, front contact E3 of relay RSI-IS and terminal C.

Assuming that crossover 3 occupies its reverse position to establish the route from signal LBB to signal RB2, and sections IT and IT are unoccopied and the route relay LBI-IS associated with signal L8 is picked up, ignal control relay LBSH is provided with a circuit that extends from terminal B over front contact 52 of relay R2M, back contact 53 of relay RZHS, front contact 46 and reverse polar contact '34 of indication relay SKR, back contact 62 of relay STE, front contact 63 of relay LGHS, contacts 64 and 65, front contact of relay ITR, front contact 78 of reverse switch repeater relay 3RKP, winding of relay LBBH, front contact 61 of relay LBHS and to terminal C. In the event route relay RZHS is picked up with crossover 3 in its reverse position, then the signal control relay RBZH is provided with a circuit that includes terminal B, contacts 88, B9, 62, I4, 46, 41, 4'8, 69, ll, '18, winding of relay RBZH, front contact 51' of relay RZHS and terminal C. It is to be seen therefore that each signal control relay is picked up for operating the corresponding signal to a proceed position when the associated route relays, the track relays for the sections of the route, the associated approach locking relays, and the repeater and indication relays for the switches of the route are all properly positioned.

The circuits for the route relays HS which govern the networks of Fig. 6 are shown in Fig. '7. Each trafiic route is provided with two route relays, one for each end of the route. The two route relays of a route are controlled by two manually controlled means one for each end of the route and by the repeater relays for the switches and signals of the associated route. Such manually controlled means may be levers of an interlocking machine, relays of a relay type of interlocking or relays of a remote control or centralized traffic control system. In the present embodiment of the invention the manually controlled means comprise relays of a centralized traflic control system of a suitable code type and which system is provided with coding units through which relays are selectively controlled according to different codes transmitted from a remote ofiice, there being a coding unit CUI associated with the left-hand end of the track layout of Fig. 1, and a unit CU2 associated with the right-hand end of the track layout. A pair of code responsive relays is provided in each coding unit for controlling the circuit network of each route relay, such code responsive relays being identified by the reference character L with a distinguishing prefix. For example, route relay RZHS used to control the signal control relays of signal R2 is controlled by a normal code responsive relay NRZL and by a reverse code responsive relay RR2L of the coding unit CUI. Similarly, route relay RBI-IS used to control signal R8, is controlled by a normal code relay NRBL and a reverse code relay RR8L of unit CUi. At coding unit CU2, normal code relay NLfiL and reverse code relay RLSL govern route relay LSI-IS which in turn is used to control signal L8, and normal code relay NLZL and reverse code relay RL2L govern route relay LZHS which is associated with signal L2.

While the centralized trafiic control system may use any one of several different types of codes by which each unit and a particular relay of the unit are selected it is contemplated that each code relay L is biased to a released position and is energized and picked up during the transmission of the code impulse that selects the relay and the relay is then released when the code impulse ceases. The arrangement is such that each code relay is retained picked up for a predetermined time interval which ordinarily may be of the order of a few seconds. Each route relay is energized over a pick-up circuit and a stick circuit, which circuits in turn are controlled by the associated code relays at the two ends of the associated route.

Assuming the crossover 3 occupies its normal position, the route relays RZI-IS and LZHS are associated with the opposite ends of the route between signals R2 and L2. To select route relay RZHS for establishing trafiic from signal R2, code relay RRZL is selected by the appropriate code and relay RR2L when picked up forms a pick-up circuit for route relay RZHS, such pickup circuit extending from terminal B over back contact 19 of code relay RLZL at the other end of the route, back contact 89 of the opposing route relay L2HS, front contact 8! of signal repeater relay LZGP, front contacts 82 and 83 of switch repeater relays 3W'PZ and 3NKP, respectively, front contact 84 of signal repeater relay RZGP, winding of route relay RZHS, and front contact 85 of code relay RRZL to terminal C. The picking up of relay RZHS completes the circuit network for signal control relay RAZH (Fig. 6) and that relay in turn on picking up causes the signal RA2 to be operated to a proceed position and signal repeater relay R2GP to be released. (Figs. 4 and 5.) The release of relay RZGP completes the stick circuit for relay RZHS, such stick circuit including terminal 13, front contact 86 and winding of relay RBI-IS, a second front contact 87 of relay RZHS, back contact 88 of relay RZGP, back contact 99 of code relay NRZL and terminal C. Consequently when code relay RR2L is released at the end of the code impulse that selects that relay, the route relay R2HS is retained energized over its stick circuit providing the associated signal HA2 has cleared. In the event there is a failure in clearing signal RAZ, then route relay RZHS is released at the end of the code and the code influence is annulled. That is, the apparatus assumes its normal condition and a new code must be transmitted in order to eiTect the control for signal RAE. In other words, the code is not stored and a hidden lockout condition cannot arise due to the failure of the signal to clear.

If traific over this route on track EB with crossover 3 normal is to be established from signal L2, code relay RL2L is selected by the proper code and a pick-up circuit is formed for route relay L2HS from terminal B over back contact 9! of code relay RR2L at the other end of the route, back contact 9| of the opposing route relay RZHS, contacts 84, 83, 82 and BI, winding of relay LZHS, and front contact 92 of code relay RLZL to terminal C. As explained in connection with Figs. 4, and 6, the picking up of route relay LZI-IS completes the network for signal control relay L2H which in turn causes signal L2-to be operated to its proceed position and signalrepeater relay LZGP to be released. Release of repeater relay LZGP closes the stick circuit for relay LZHS from terminal B over front contact 94 and winding of relay LZHS, a second front contact 95 of relay LZI-IS, back contact 95 of relay L2GP and back contact 97 of code relay NLZL to terminal C. Hence route relay LZHS is retained energized subsequent to the release of code relay RLZL at the end of the codeimpulse providing relay L2H is picked up to clear signal L2 and release relay LZGP, but if such operation is not effected then route relay L2HS is released and the code control is annulled.

When crossover 3 is at its normal position route relays R8HS and L8HS are associated with the route of track WEB between signals R8 and L8, and which relays are controlled by the associated code relays in substantially the same way as just explained in connection with the control of route relays E2118 and LZHS and the description for the control of route relays E8118 and L8HS need not be made in detail. It is to be noted, however, that the pick-up circuit for route relay R8HS includes back contact 93 .of code relay RLBL at the opposite end of the route, back contact 99 of the opposing route relay LBHS and front contact 100 of the associated code relay RRBL; 7 5" and that the stick circuit for relay RSI-IS includes back contact I0! of signal repeater relay RBGP. Also that the pick-up circuit for route relay LSHS includes back contact I92 of code relay RRBL at theother end of the route, back contact I93 of the opposing route relay RSHS and front contact I94 of the associated code relay RL9L; and the stick circuit for'relay LBHS includes back contact 195 of signal repeater relay L8GP.

In the case the crossover 3 occupies its reverse position to form the route from signal LE8 to signal RBZ, route relays R2HS and L8HS are associated with the opposite ends of the route. Under such set-up of the track layout the pick-up circuit for route relay LBHS is formed from terminal B over back contact 90 of code relay RRZL, back contact 9| of route relay RZHS, front contact 84 of relay RZGP, front contact H36 of the reverse switch repeater relay 3RKP, front contacts I97 and H38 of relays 3WPZ and L8GP, respectively, Winding of relay LBHS and front contact I04 of relay RLBL to terminal C. The stick circuit for relay L8HS includes back contact W5 of signal repeater relay L9GP, the same as previously pointed out. If traffic is to move from signal RBZ, then route relay RZHS is selected by a pickup circuit including back contact 93 of relay RLBL, back contact 99 of relay LfiHS, contacts I08, 101, I06 and 84, winding of relay RZHS, front contact of code relay RRZL and terminal C. The stick circuit for relay RZHS is completed at back contact 88 of signal repeater relay R2GP as previously traced.

Still referring to Fig. 7, the switch controlling relays 3NWS and, 3RWS which control the position of crossover 3 as explained hereinbefore, are controlled by code responsive relays of the centralized traific control system and which relays are shown as being included in the coding unit CUI, When a normal switch code relay N3L and a code delivery relay DR of unit CUI are picked up in response to a particular switch code, a pickup circuit is formed from terminal B over front contact I09 of relay N3L, front contact H9 of relay DR, winding of relay 3NWS and to terminal C, and relay 3NWS is energized and picked up. Relay 3NWS is retained energized subsequent to the code impulse over a stick circuit that includes terminal B, back contact Ill of relay DR, back contact H2 of relay SRWS, front contact] 13 of relay SNWS, winding of the relay and terminal C. In like fashion reverse switch controlling relay 3RWS is energized over a pick-up circuit including contacts of the code relays R3L and relay DR and which pick-up circuit includes terminal B,

position, track section IT is unoccupied and that it is desired tomove a train on track EB past signal RA2, it being further assumedthat the signal and switch repeater relays are all properly energized and picked up. The operator transmits a code to select code relay RRZL of coding unit CD1, and which code relay on picking up completes the pick-111),, circuit for route relay RZHS (Fig. '1) and relay RZHS on picking up completes the network .(Fig. 6) for signal control relay RAZH which in turn causes sign'alRAl to be operated to aproceed-positicn andsignal repeater relay RZG-P to be released (Figs. 4 and 5). With relay RZGP released, the stick circuit for route relay RZHS is formed beforethe code relay RRZL releases, and the signal is retained at its proceed position to govern the traflic into the respective route. It is to be observed that should the operator desire to set signal EA! to stop after having cleared the'signal in the manner explained above, he can do so by transmitting a code that selects relay NR2L, which relay .on picking up opening back contact 89, opens the stick circuit for route relay RZHS causing that relay to be released toopen the circuit for the signal control relay vRAZI-I. As explained hereinbefore, should there occur a failure in the operation of clearing signal ,RAZZ, then route .relay R2H Sis released at the end of the code and'the code control is annulled with .the result that a hiddenlockout condition cannot arise. signal HA2 cleared, .and .thectrain ,movingpast the signalinto section I52, the track relay 'lTR is shunted opening the network for the signal control relay RAZH (Fig. 6). causing the signal to beset to stop and the repeater relay RZGP to With be, reenergized, which latter relay .on picking up opening back contact 88 opens the stick circuit for route relay, RZHS and relay RZHS is released to its normal position, It is .to be observed that approach locking .relay 3.2M is controlled .in the manner explained inconnection with Fig. 3 and enforces the usual. approach locking. It is-also to be observed that while signal RA2 is cleared and relay RZHS ;held energized by its stick circult, and if the operator inadvertently transmits a code for relay RLZL in an attempt to control relayLZI-IS to clear the opposing signal L2, such inadvertent operation does not causerelay LZHS to be picked up because its pick-up circuit is held open by back contact 9! of relay RZHS and also .does not disturb theenergized conditionof the route relay RZHS because relay RZHS is heldenergized by its stick circuit.

If in place of clearing signal 'RA2 for a train ontrack EB, it is desired to establishtraific in the other direction past signal L2, then the operator transmits a code for selecting relay RLEL of unit CU2 .to complete the pick-up circuit for route relay LZHS. Relay LZHS on picking-up-completes the network (Fig.6) for signal control relayL2I-I and that relayon picking upcauses signal L2 to be operated to aproceed position and repeater relay L2GP to bereleased. The release of relay LZGP completes the stick circuit for'relay LZI-IS to retain the relay picked up and the signal at its proceed position subsequent to the release of the code relay RLZL. The-operation of the apparatus associated with route relay LZHS is substantially the same as that describedin connec tion with the operation of the apparatus associated with route relay REHS. Furthermore'the operation of the apparatus and circuits associated with the route between signals R8 and L8 when thecrossover 3 is at its normal position is substantially the same as the operation of the apparatus and circuits associated with the route between signals R2 and L2.

I shall next assume that it is desired to establish the route over the crossover 3 in reverse position. The operator wouldfirst transmit a code to control the reverse switch controlling relay RWS to bringabout the reverse position of the crossover. Assuming the track sections IT and IT are unoccupied and theicrossover is in its revers position, and that it is desired to control signal :LBS to its proceed position to move a train over :the cross-over, the operator transmits a code for selecting .relayRLBL tocomplete the pickup circuit for route relay LBHS, such pickup circuit being completedoverfront contact I06 of the reverse switch, repeater relay 3RKP. "Relay LBI-IS when picked up completes the control network for signal control relay LBBI-I (Fig. .6) and signal .LBB is operated to a proceed position and repeater relay L8GPis released. The release of relay LBGP completes the stick circuit for relay LBI-IS and that relay is retained energized subsequent to the code and signal LBS is held at its proceed position. If it isdesiredto control signal R132 to move a train over :the crossover in its reverse position, code relay RRZL is selected to pick up route relay-RZHS. The operation of the apparatus following the picking up of route relay RZHS is similar to that described in connection with controlling signal LBBby route relay LBHS.

Again it is to be noted that if crossover 3 is normal and signal HA2 cleared in the manner explained hereinbefore and the operator by mistake attempts to reverse the crossoverand clear signal LBS for a move over the crossovensignal LAB, which would ordinarily clear by such a signal control with the crossover normal, cannot be cleared because of the deenez gizing of the check relay 3WPZ.

It is to be seen, therefore, thatl have provided railway trafiic controlling'apparatus incorporating novel means for controlling the signals at the opposite ends of a route over which trafiic may move in either direction and by which apparatus the so-called hidden lockout condition cannot arise and a train cannot be directed through a wrong route.

Although I have herein shown and described only one form of railway trafiic controlling apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: g

1. In combination, a traffic route over which traffic may move i i-either direction, a signal at each end of the route to govern ,trafiic over the route, a route relay :for each end of the route effective when picked ,up to control the signal c at d wi t e same end ,of the route to a proceed positioma signal repeater relay for each signal and picked up when :the associated signal is at stop and released'when the signal is at proceed, a manually controlled means for each end of the route and each Qf'WhiQh means is operable to a normal condition and to an operated condition; a pick-up circuit for ach route relay and each of which pick-up circuits includesa contact closed at the operated condition of the manually controlled means for the same end of the route as the route relay, afrontcontact of each of the signal.repeaterrelaysandacontact closed at the normal condition ,of ;.the manually controlled meansfor the otheriendof theroute; and a stick circuit, for each route relay .and each of'which stick oircuitsgincludes aback contact of the signal repeater relay for the signal associated with the same end of the route as .the route relay and a contact closed .atthe normal condition of the manually controlled means Ifor the same end of the route.

2.. In combination, .a traflic route over which trafiic may move in'eitheri-direction, a signal at each end of the route to govern traific over the route, a route relay for each end of the route eiiective when picked up to control the signal associated with the same end of the route to a proceed position, a signal repeater relay for each signal and picked up when the associated signal is at stop and released when the signal is at proceed, a normal and a reverse manually controlled relay for each end of the route and each or which manually controlled relays is biased to a released position and is energized and picked up for a predetermined interval only in response to a preselected code; a pick-up circuit for each route relay and including a front contact of the reverse manually controlled relay for the same end of the route, a front contact of each of the signal repeater relays and a back contact of the reverse manually controlled relay for the other end of the route; and a stick circuit for each route relay and including a back contact of the signal repeater relay for the signal associated with the same end of the route as the route relay and a back contact of the normal manually controlled relay at the same end of the route as the route relay.

3. In combination, a traffic route over which traffic may move in either direction, a signal at each end of the route to govern traflic over the route, a route relay for each end of the route effective when picked up to control the signal associated with the same end of the route to a proceed position, a signal repeater relay for each signal and picked up when the associated signal is at stop and released when the signal is at proceed, a normally released code responsive relay for each end of the route and each of which code relays is adaptable of being picked up for a predetermined time interval and then released in response to a preselected code, a pick-up circuit for each route relay and each of which pick-up circuits includes a front contact of the code responsive relay for the same end of the route as the route relay and a back contact of the code responsive relay at the other end of the route,

and a stick circuit for each of said route relays and each of which stick circuits includes a back contact of the signal repeater relay for the signal associated with the same end of the route as the route relay to retain the route relay energized only when the associated signal is operated to a proceed position during said predetermined time interval.

4. In combination, a traffic route over which traflic may move in either direction, a signal at each end of the route to govern traffic over the route, a route relay for each end of the route effective when picked up to control the signal associated with the same end of the route to a proceed position, a signal repeater relay for each signal and picked up when the associated signal is at stop and released when the signal is at proceed, a first and a second manually controlled relay for each end of the route and each of which relays is biased to a released position and adaptable of being picked up in response to a code impulse of current of a predetermined duration, a pick-up circuit for each route relay and each of which pick-up circuits includes a front contact of said first relay for the same end of the route as the route relay and a back contact of said first relay for the other end of the route, and a stick circuit for each route relay and each of which stick circuits includes a back contact of the signal repeater relay and of said second relay for the same end of the route as the route relay whereby a route relay is picked up for clearing the corresponding signal to a proceed position and then retained picked up to retain the signal at such proceed position only if the signal is cleared during said predetermined duration, a signal can be set to stop in response to a code that picks up the associated second relay and operation of the first relay at the end of the route opposite a cleared signal is prevented from setting such cleared signal to stop.

5. In combination, a traffic route over which trafiic may move in either direction, a signal at each end of the route to govern traflic over the route, a signal control relay for each signal effective when picked up to cause the signal to be operated to a proceed position, a route relay for each end of the route, a circuit for each said signal control relay to pick up the relay and each such circuits including a front contact of the route relay associated with the same end of the route and a contact controlled by trafiic conditions of the route, a signal repeater relay for each signal and energized over a back contact of the signal control relay for the same signal, a normally released code responsive relay for each end of the route and each of which code responsive relays is picked up for a predetermined time interval in response to a preselected code and is then released when the code ceases, a pick-up circuit for each route relay and each of which pick-up circuits includes a front contact of the code responsive relay for the same end of the route as the route relay and a back contact of the code responsive relay at the other end of the route, and a stick circuit for each of said route relays and each of which stick circuits includes a back contact of the signal repeater relay for the signal associated with the same end of the route as the route relay to retain the route relay energized and the associated signal at proceed only when the respective signal control relay is picked up and the respective signal repeater relay is released during said predetermined time interval.

EARL M. ALLEN. 

